Process of manufacturing pitch.



TATTE Patented February 28, 1905.

ATTET SPECIFICATION formingpart of Letters Patent No. 783,916, datedFebruary 28, 1905. Application filed June 22, 1903- Serial No. 162,590.

To all whom, it may concern;

Be it known that T, Gnone VON WIRKNnR, doctor of philosophy,a subject ofthe Emperor of Austria ,Hungary, residing at idchallre, l Vestphalia,Germany, (Whose post-office address is Fabrikdirector Dr. Georg VonVVirkner, Schalke, Westphalia, Germany,) have in vented a certain newand useful Process for the Manufacture of Pitch, (for which I haveapplied for a patent in Germany on the 7th day of March, 1903,) of whichthe following is a specification.

lit is well known that the aifinity of sulfuric acid to water is sogreat that the acid abstracts from many substances hydrogen and oxygenwhile forming Water. According to the present invention these propertiesof sulfuric acid are utilized for the conversion of tar, tar-oils, andsimilar matters into pitch. The details of procedure in ordinary casesmay be 'as follows: The raw material to be converted into pitch isheated with a quantity of sulfuric acid to be ascertained by apreliminary experiment, carried out as followsz'A test sample of the rawmaterial is heated with about ten per cent. of sulfuric acid in a smallreceptacle to about 180 or higher. If the result is not satisfactory asregards the yield and the desired consistency, the experiment isrepeated with a slightly larger quantity of acid. If this experimentdoes not give a satisfactoryresult, a third experiment is made with astill larger quantity of acid, and so on until the quantity of acidrequired has been ascertained. The acid is added to the raw material inthe cold or caused to flow into the preheated raw material at once orgradually, and the heating of the mixture is continued until thesulfuric acid has been decomposed and until any volatilesubstances whichmay have remained undecomposed or which may have split off in the courseof the reaction have been distilled off sufficiently to leave a residueof the desired consistency or thickness. For this purpose any knownoperations hitherto used, for instance, in the distillation of coal-tar,for distilling the tar down to the consistency of pitch may of coursefind appropriate application in carrying out my present invention.

The strength of the sulfuric acid used is immaterial for the result ofthe reaction, because in. using dilute sulfuric acid theexccss of waterwill be evaporated and the acid concentrated by the heat employed in theproc ess. As a rule it will be found ad-mntagcous to use concentratedacid.

Giving to the great variation in the composition of the raw materialssuitable for treatment by the present process no definite or accuraterule can be given as regards the quantity of sulfuric acid required ineach case and as regards the quantity of hpat or the temperature to bemaintained, except that the temperature should be about 180 Centigradeor higher. As mentioned above, these proportions or requirements have tobe ascertained for each particular raw material to be employed by meansof a preliminary experiment. These conditions depend also in a greatmeasure on the nature of the final product to be obtained that is tosay, Whether soft, medium soft, or hard pitch is required.

By the present process tar, tar-oils, and similar material may be easilyconverted into pitcln The following examples havegivcn good results:

First. Three hundred parts of tar-oil (anthracene-oil) having a specificgravity of 1.120 to 1.125 were mixed with one hundred and two to onehundred and eight parts of sulfuric acid of 6O Baum and gradually heatedto a temperature approaching 300* centigrade. The water split off theoil or introduced with the acid escapes first, while producing violentebullition; At the same time the generation of sulfurous acid becomesnoticeable and continues to the end of the reaction, which moment may,as a rule, be recognized by the frothing of the residue; but the surestway of recognizing the end of the process is totest samples taken fromthe residue by introducing a drop of the same into cold water andexamining the hardness or consistency of the product thus obtained. Theapproximate duration of the process is from one and one-half to twohours.

Second. Three hundred parts of coal-tar a re heated to about 180 to 200centigrade, theness of obtaining pitch from tar and certain tar productsor similar raw materials, and the product thus obtained has a highermarket value and is more salable.

It has been previously proposed to treat tar with sulfuric acid in thecold or at a moderate heat in order to produce pitch; but the result ofthis treatment is only an intermediate proddiately yields the finalproduct.

not, which is afterward subjected to a complicated supplementaltreatment with a comminuted metal in the presence of "Waterforthepurpose of neutralizing the sulfuric acid, which is subsequently washedout in the shape of a sulfate, after which the product has to bedistilled until it possesses sufficient hardness. In my process theproduct obtained by heating the raw material With sulfuric acid imme' Itis free from sulfuric acid, because the sulfuric acid has been removedin the course of the process by complete decomposition, and the productis not subjected to any supplemental treatment.

What I claim is- 1. The process for obtaining pitch from taroils andsimilar materials, which consists in heating the same with a suitablequantity of sulfuric acid to a temperature of about '180 centigrade atleast, until the sulfuric acid is decomposed and a sufiicient quantityof the volatile bodies has been distilled off to leave a pitch of thedesired consistency, substantially as described.

2. The process of obtaining pitch from taroils and similar materials,which consists in heating the same with a desired quantity of sulfuricacid until the said acid decomposes, and a sufficient quantity of thevolatile bodies has been distilled off to leave pitch of the desiredconsistency.

In witness whereof I have hereunto signed my name in the presence of twosubscribing Witnesses.

enone VON .WIRKNER.

Witnesses:

MARCELL FELTEN, -VICTOR SCHWANDNER.

